In the morning Max woke with an idea, and since she woke just before dawn, the idea was extra sticky. Before the others were awake, she slipped on her shoes, padded out through the deserted café, and raced through the shuttered streets back to Great-Aunt Elodie’s house. Two sleepy police officers were on guard, because the whole place had to be searched for stolen goods, and they didn’t want any of the other Phantoms removing anything overnight.

Max, out of breath, panted her idea to them.

“Well,” said one, yawning, “If you’re sure he wants them, then fine. They’ve got to go somewhere.”

“He will,” said Max. She didn’t know for sure, but she was an optimist.

The others were up early, and for the rest of the day, Max and Sister Marguerite explored Istanbul. Salem had to stay and look after the café, but they invited Rupert, Ester and Klaus. Ester declined – “Just because we’re on the same side,” she blared, “doesn’t mean I want to traipse round Istanbul with you pointing at things and smiling” – but Klaus was free to go now that her jewels were safe, and Rupert came too.

Max finally saw the Istanbul that she had read about in her armchair. They had to dash from place to place, but once they had arrived somewhere, Max slowed down, trying to learn every detail by heart. It made her feel slightly desperate to think she might ever forget. She saw all the famous sights. She lingered in the morning light that filtered through the stained glass of the Blue Mosque; she felt herself shrink a little under the huge painted dome of Hagia Sophia; she let herself be flooded right through with every colour in Topkapı Palace. She lost Sister Marguerite for at least half an hour in the heaving halls of the Grand Bazaar, but found her in the end, haggling over some sheets of black fabric for a new habit.

Max loved seeing all the famous buildings, but she loved it best when they came unexpectedly upon colourful streets that slid steeply downhill towards the Bosphorus Strait; streets that felt, as you stood at their crest, like they were the beginning of something exciting. She could generally persuade the others to race her down them. Klaus was slow and lumbering, but Marguerite and Max were well matched – and the winner was always Rupert, by a long way.

“Still homesick?” asked Sister Marguerite, as they caught their breath after an especially close race.

Max considered this. She missed her home, but there wasn’t a knot in her stomach any more.

“No,” she said, “I don’t think so. At least, it doesn’t feel like sickness any more. I just know, kind of in the back of my mind, that there’s something important I’ve left behind.”